Gas-blast circuit breaker with multiple interruption



Aprilzz, 1969 ARL-D|TER FLE-SSEL ETAL I 3,440,379

Filed Aug. 9, 1966 GAS-BLAST CIRCUIT BREAKER WITH MULTIPLE INTERRUPTION Sheet` of3 CurL-Dl'eer F'lesset, Gerhard Mauhe www, VLM x. 19o/JZ; am,

April 22, 1969 cARL-mETER FLESSEL ET AL 3,440,379

Filed Aug. 9, 1966 GAS-BLAST CIRCUIT BREAKER WITH MULTIPLE INTERRUPTION Cou'L-D/'ekerI FlesseL Gerhard. Mal/the PM, JW x, PMAM April 22, l969 CARL-DIETER FL'oEssEl. ET AL 3,440,379

GAS-BLAST CIRCUIT BREAKER WITH MULTIPLE INTERRUPTION Car-L- Dl'ezer Flessel, Gerhard Mauth@ www, W29 im@ www United States Patent O 3,440,379 GAS-BLAST CIRCUIT BREAKER WITH MULTIPLE INTERRUPTION 'Carl-Dieter Flessel, Fislisbach, and Gerhard Mauthe, Neuenhof, Switzerland, assignors to Aktiengesellschaft Brown, Boveri & Cie, Baden, Switzerland, a joint-stock company Filed Aug. 9, 1966, Ser. No. 571,290 Claims priority, application Switzerland, Sept. 6, 1965, 12,395/ 65 Int. Cl. H01h 33/80, 33/83 U.S. Cl. 200-148 4 Claims The invention concerns a gas-blast circuit breaker with multiple interruption where the power switching points are arranged in pairs in switch chambers which are kept under gas pressure and with an auxiliary switching point in series with a resistor located in parallel with each power switching point, at least the auxiliary switching point being in an auxiliary switch chamber which is also constantly subjected to a gas pressure. The hollow, stationary switching elements belonging to the power interrupting points and directed towards each other are provided with a common exhaust valve which opens for a short time. It is known to assemble gas-blast circuit breakers with multiple interruption in such a manner that their power switching points are arranged in pairs in so-called double extinguishing chambers. It is usual to keep these chambers constantly lled with an arc-extinguishing gas under pressure. Moreover, it is known to construct at least the stationary switching contacts of the power interrupting points in the form of hollow nozzle tubes and to arrange them in such a manner that they are directed towards each other inside a switch chamber that contains two power interrupting points. These switching contacts which come together in the middle of the switch chamber have at this point a common exhaust valve which, when the breaker opens, connect the interior of the nozzle tube temporarily to the atmosphere, so that the switching gases which flow through the nozzle tubes can be discharged by way of the open valve to the atmosphere. It is also usual to connect a resistor arranged in series with an auxiliary switching point in parallel with each power switching point. Thereby it is possible to locate either only the auxiliary switching point or also the resistor in an auxiliary switch chamber, the latter being constantly lled with pressure gas.

The auxiliary switching points serve to connect the resistors in parallel with the power switching points when the breaker opens and to disconnect them again after the opening operation, so that they are not continuously under voltage. Conventional auxiliary switching points are provided for this purpose with their own actuating mechanism. With separate drives it is, however, diilicult to adjust these in such a manner that the switch contacts of the auxiliary switching points operate simultaneously both mutually and as regards the power interrupting points. Also a separate actuating mechanism for each auxiliary switching point involves considerable costs both as regards fabrication and assembly.

The object of the present invention is to remedy this and provide a simple and cheap solution for actuating the auxiliary switching contacts, whereby at the `same time it is possible to subject the auxiliary switching points to a gas-blast. In accordance with the invention it is proposed to couple the movable hollow auxiliary switching contacts mechanically with the movable exhaust valve in such a manner that the auxiliary switching points are closed when the exhaust valve is open and that the ends of the auxiliary switching contacts which are directed towards each other extend into a space which, when the exhaust valve is open, is in communication with the atmosphere by way of a 3,440,379 Patented Apr. 22, 1969 hollow rod that serves as a coupling for the exhaust valve element.

The invention is further explained by means of the attached drawings wherein:

FIGURE 1 shows the improved gas-blast circuit breaker in vertical section;

FIGURE 2\ shows further constructional example according to the invention also in vertical section; and

FIGURE 3 is a partial view in section of a modified embodiment of the invention shown to a larger scale.

With reference now to FIGURE 1 two switch chambers 3 are seen to be symmetrically mounted on a hollow supporting insulator 1 with the aid of an intermediate piece 2. Each switch chamber contains a stationary switch contact 4 and a movable switch contact 5. The switch contacts 4, 5 form a power interrupting point. The movable switch contact 5 is connected by way of a rod 6 to a driving piston 7 which is subjected to the pressure of a spring 8. Reference numeral 9 indicates a sliding contact which conducts the current from the switch contact 5 to the external terminal 10, and 11 is a tubular valve element which, by means of ribs and a rod, is connected to the piston 12. Control pipe 13 communicates both with the space below piston 12 and the space on the right side of the driving piston 7. The other end of the pipe 13, not shown in the drawing, is connected to a conventional control valve. A valve casing 14 is mounted on the middle of the intermediate piece 2. It isprovided with openings 15 which communicate with the outside air and, in the position shown, are shut off from the inside of the stationary hollow switch contacts 4 by the valve element 16. The hollow rod 17 connects on the one hand the valve element 16 rigidly to the piston 18 which is under the influence of the recall spring 19, and on the other hand the upper end of rod 17 is connected to bell crank levers 20 pivoted at 21, the other ends of these levers being hinged to the movable hollow auxiliary contacts 23. Pipe 22 is connected at one end to the space below piston 18 and at the other end, not shown, to a conventional control valve. The ends of the hollow auxiliary contacts 23 project into the chamber 24 which is in communication with the atmosphere by way of hollow rod 17 as soon as Valve 16 is lifted from the seat 16a. Movable auxiliary switch contact 23 together with the stationary auxiliary switch contact 25 forms an auxiliary switching point which is in series with the resistor 26. Parts 23, 25, 26 are inside the auxiliary chamber 27 which communicates with switch chamber 3 by way of pipe 28 which also acts as a current lead.

The arrangement shown in FIGURE 1 operates as follows: In the position shown, the circuit breaker is closed. The power interrupting contacts 4, 5 are closed, whilst the auxiliary switch contacts 23, 25 are open. Switch chambers 3 as well as auxiliary switch chambers 27 are lled with pressure gas, since the hollow supporting insulator 1 is connected to a pressure gas reservoir, not shown in the drawing. In order to open the breaker, pressure -gas is allowed to flow through control pipes 13, 22n to the underside of pistons 7, 12 and 18 respectively. Piston 18, due to its upward movement, causes valve element 16 to be lifted from the seating ring 16a so that the interior of the hollow switch contact 4 is in communication through the openings 15 with the atmosphere and is thus vented. Parts 16, 16a therefore form a common exhaust valve for the hollow switch contacts 4. At the same time space 24 is also vented by way of the hollow rod 17, and the hollow auxiliary switch contacts 23 coupled to rod 17 by crank levers 20 are brought into the closed position. In this position the hollow auxiliary contacts 23 are practically shut oi in a sufficiently gas-tight manner by the stationary hollow auxiliary contacts 25 so that no appreciable amount of gas can flow from the auxiliary chamber 27 through the hollow contactsj 23 into the space 24. The pneumatic conditions in the control pipes 13, 22 are mutually so adjusted that the auxiliary switching points 23, 25 are already closed when the power interrupting points 4, 5 are open. Whilst the switch contacts 5 are brought into the open position by the movement of their pistons 7, the outer exhaust valves 11 open simultaneously due to the movement f their pistons 12. The arc which forms between the contacts 4, '5 is subjected to a gas-blast due to the gases flowing to the atmosphere on the one hand through the hollow movable contact and the outer exhaust valve 11 and on the other hand through the hollow stationary contacts 4 by way of the middle common exhaust valve 16. After a prescribed time of about 40 microseconds valves 11 close again, because their pistons 12 are provided with a bore-hole through which pressure gas passes to the other side of the piston whereby the pressure on both sides of the piston 12 is equalized, so that spring 12a closes the valve. Since drive piston 18 of the middle exhaust valve 16, 16a also has an equalizing bore-hole, this valve closes after a short time under the pressure exerted by spring 19', so that the auxiliary switching points 23, 25 are opened again. The gas-blast for the arc which occurs at the auxiliary switching points is produced by the gases which can flow through the hollow auxiliary switching contacts 23 into the space 24 which is already in communication with the atmosphere.

For the closing operation, control pipes 13, 22 are vented. Whilst the outer exhaust valves 11 and also the middle common exhaust valves 16, 16a are closed and remain inoperative and thus also both movable auxiliary switch contacts 23 retain their open position, only the power switching points 4, 5 are closed under the action of the springs 8.

With the construction shown in FIGURE 1, the cornmon exhaust valve is opened for a short time during the opening operation and, due to the coupling with the auxiliary switching contact which switches the resistor in parallel with the power switching point for a short time, it becomes effective as a disconnecting resistor. When the power switching point is closed, the exhaust valve remains, however, closed and the auxiliary contact open, so that the resistor is not effective. l'n certain cases, however, it is desirable to use the opening resistor also as a closing resistor, that is to close the auxiliary switching contacts shortly before the power interrupting point is closed and after it is closed to reopen the auxiliary switching point again. This is achieved by providing the hollow rod with an actuating piston that has a bore-hole, the piston being located in a cylinder where the space below the piston is connected by way of a non-return valve which opens in the inflow direction and the space above the piston is connected by way of a non-return valve which opens in the outflow direction to the control pipe.

In the modified construction of FIGURE 2 the elements which correspond to those shown in FIGURE 1 are designated by the same reference numerals. The control pipe 22 which communicates with the space 32 below the perforated piston 18 contains the non-return valve 30 which can open in the inow direction. Space 33 above piston 18 is in communication with control pipe 22 by way of a pipe 35 and the non-return valve 31, which opens in the direction of pipe 22. This latter valve can only open when pressure gas Hows back from space 33 into control pipe 22.

This results in the following method of operation: When,

as already described, for opening the breaker, pipes 13 and 22 are supplied with pressure gas, then on the one hand contacts 4, 5 of the power switching points separate, whereby on the other hand piston 18 moves upwards in cylinder 34 so that exhaust valve 16 opens and the auxiliary switching contacts 23 which are coupled by means of hollow rod 17 and crank levers 20 are brought into the closed position. They establish. brief contact with the stationary auxiliary contacts 2S, so that resistors 26 come into operation. After a short time exhaust valve 16 is thus closed again and auxiliary switching points 23, 25 are reopened, since the gas pressure in spaces 32, 33 on both sides of piston 18 becomes equalized so that spring 19 returns piston 18 to the position shown. If now the pressure gas is discharged from the control pipes 13, 22 for the switching-in operation, then pressure gas also escapes from space 33 by way of pipe 35 and non-return valve 31 which now opens, so that the pressure in space 32 which can only decrease slowly through the hole in piston 18 moves the latter upwards. As a result, auxiliary switching points 23, 25 are closed and resistors 26 act as closing resistors, because the auxiliary switching points 23, 25 close somewhat sooner than the power switching points 4 and 5, this being easily achieved by suitable dimensions. After the pressure in spaces 32, 33 has become equalized by way of the hole in piston 18, spring 19 moves the auxiliary contact 23 back into the open position. Since the exhaust valve 16 during the closing operation of the breaker executes a short opening movement, the switching-in arc is subjected to a gas-blast. In certain cases it is, however, possible to omit the gas-blast whereby a saving in pressure gas can be achieved.

FIGURE 3 illustrates such a modified form of the invention. The same elements as in FIGURE 2 are designated by the same reference numerals. The hollow rod 17 together with its piston y18 is located in cylinder 34. lIn this case it is, however, not connected to the exhaust valve 45 but can slide inside the latter. Exhaust valve 45 possesses a piston 40 which is rigidly connected to it and has a borehole 40a, whereby space 32 is shut off from space 44. The latter is in communication with chamber `43 by way of a passage 42. During an upward movement, rod 17 is also moved upwards by the valve 45l due to the intermediate ring 41. When for the switching-out, control pipe 22 is supplied with pressure gas, the gas passes through the non-return valve 30, which commences to open, into the space 32 below piston 40 and opens on the one hand exhaust valve 45 and lifts on the other hand rod 17, whereby the auxiliary switching contacts 23 are brought into the closing position by `way of crank levers 20. During this process, piston 18 does not perform any Work. After a short time, spaces 44 and 43 are lilled with gas which passes through boreholes `40a and 18a and also chamber 43 is lled by way of passage 42. Spring 19 returns rod 17 and exhaust 4S to the position shown in the ligure. Pressure gas also passes through borehole 45a to the upper side of exhaust valve 45 and keeps it closed due to the larger effective surface. When during the switching-in operation the gas is vented from control pipe 22, nonret'urn valve 31 opens and space 33 is rapidly vented by way of pipe 35 so that piston 18 and thus rod 17 are forced upwards. Space 44 and chamber 43 serve to provide the necessary driving volume, because the pressure gas can only escape slowly through the borehole 18a. Exhaust valve 45 therefore remains stationary, because as already stated it is maintained in the closed position by a pneumatic force. After a short time, the gas in spaces 32, 33, 44 also escapes through boreholes 18a, 40a and 42, so that spring 19 moves rod 17 back into the position shown, whereby auxiliary switch contacts 23 are caused to move into the open position.

The constructional form according to FIGURE 3 enables, by omitting the intermediate ring 41, the circuit breaker to be modified in such a manner that the resistor is only effective during the switching-in operation in that when switching-out, the exhaust valve only opens briefly as described without causing rod 17 to be moved and auxiliary contacts 23 to be closed.

We claim:

1. In a circuit breaker of the gas-blast type, the combination comprising at least two pairs of relatively movable power switching contact members located within a gas-pressurized main switching chamber and interconnected to establish two series connected power switching points, one of sai-d contact members of each pair being stationary and of the nozzle tube type with its nozzle end adapted to be engaged with and disengaged from the other contact member, the other ends of said stationary nozzle tubes terminating in a common exhaust valve through which the gases in said switching chamber are exhaused to atmosphere when said contact members disengage, an auxiliary switching point -for each power switching point, each said auxiliary switching point being constituted by a pair of relatively movable auxiliary contact members located within a gas-pressurized auxiliary switching chamber, one of said auxiliary contact members of each auxiliary switching point being of the tubular type with one end thereof adapted to be engaged with and disengaged from the other auxiliary contact member, a resistor connected in a series circuit lwith said auxiliary contact members and which series circuit is connected in parallel with the contact members of the corresponding power switching point, and means mechanically coupling said common exhaust valve with said tubular auxiliary contact members to eiect simultaneous actuation thereof so that said auxiliary contact members engage when said exhaust valve is opened, said coupling means including a tubular rod having one end thereof in communication with the interior of said tubular auxiliary contact members and other end in communication with the atmosphere by way of said exhaust valve when opened.

2. A circuit breaker of the gas-blast typey as deiined in claim 1 wherein the end of said tubular rod remote from said common exhaust valve terminates in a chamber and in which is included a mechanical linkage interconnecting that end of said tubular rod with said tubular auxiliary contact members.

3. A circuit breaker of the gas-blast type as defined in claim 1 and which includes a drive means for said tubular rod constituted by a drive piston to which said tubular rod is connected and a cylinder in which piston operates, said piston including a bore through which the portions of the interior of said cylinder on opposite sides of said piston are placed in communication with each other, the interior of said cylinder at one side of said piston being placed in communication with a supply pipe for pressurized gas by way of a non-return valve opening in the in-ow direction of the gas into said cylinder, and the interior of said cylinder at the other side of said piston also being placed in communication with said pressurized gas supply pipe by way of a non-return valve opening in the out-flow direction of the gas from said cylinder.

4. A circuit breaker of the gas-blast type as dened in claim 3 wherein said cylinder includes a second piston surrounding said hollow rod, said second piston being connected directly to said exhaust Valve for actuating it to open position and being indirectly coupled to said drive piston for said tubular auxiliary contact members by a sleeve slidable on said hollow rod.

References Cited UNITED STATES PATENTS 3,054,877 9/1962 Thommen 200-148 3,163,737 12/1964 Gonek et al. 3,211,869 10/1965 Gonek et al. 200-148 3,358,105 12/1967 Barker et al.

FOREIGN PATENTS 71,769 7/ 1959 France. 979,029 l12/ 1950 France.

ROBERT S. MACON, Primary Examiner.

U.S. Cl. X.R. 200-148 

1. IN A CIRCUIT BREAKER OF THE GAS-BLAST TYPE, THE COMBINATION COMPRISING AT LEAST TWO PAIRS OF RELATIVELY MOVABLE POWER SWITCHING CONTACT MEMBERS LOCATED WITHIN A GAS-PRESSURIZED MAIN SWITCHING CHAMBER AND INTERCONNECTED TO ESTABLISH TWO SERIES CONNECTED POWER SWITCHING POINTS, ONE OF SAID CONTACT MEMBERS OF EACH PAIR BEING STATIONARY AND OF THE NOZZLE TUBE TYPE WITH ITS NOZZLE END ADAPTED TO BE ENGAGED WITH AND DISENGAGED FROM THE OTEHR CONTACT MEMBER, THE OTHER ENDS OF SAID STATIONARY NOZZLE TUBES TERMINATING IN A COMMON EXHAUST VALVE THROUGH WHICH THE GASES IN SAID SWITCHING CHAMBER ARE EXHAUSTED TO ATMOSPHERE WHEN SAID CONTACT MEMBERS DISENGAGE, AN AUXILIARY SWITCHING POINT FOR EACH POWER SWITCHING POINT, EACH SAID AUXILIARY SWITCHING POINT BEING CONSTITUTED BY A PAIR OF RELATIVELY MOVABLE AUXILIARY CONTACT MEMBERS LOCATED WITHIN A GAS-PRESSURIZED AUXILIARY SWITCHING CHAMBER, ONE OF SAID AUXILIARY CONTACT MEMBERS OF EACH AUXILIARY SWITCHING POINT BEING OF THE TUBULAR TYPE WITH ONE END THEREOF ADAPTED TO BE ENGAGED WITH AND DISENGAGED FROM THE OTHER AUXILIARY CONTACT MEMBER, A RESISTOR CONNECTED IN A SERIES CIRCUIT WITH SAID AUXILIARY CONTACT MEMBERS AND WHICH SERIES CIRCUIT IS CONNECTED IN PARALLEL WITH THE CONTACT MEMBERS OF THE CORRESPONDING POWER SWITCHING POINT, AND MEANS MECHANICALLY COUPLING SAID COMMON EXHAUST VALVE WITH SAID TUBULAR AUXILIARY CONTACT MEMBERS TO EFFECT SIMULTANEOUS ACTUATION THEREOF SO THAT SAID AUXILIARY CONTACT MEMBERS ENGAGE WHEN SAID EXHAUST VALVE IS OPENED, SAID COUPLING MEANS INCLUDING A TUBULAR ROD HAVING ONE END THEREOF IN COMMUNICATION WITH THE INTERIOR OF SAID TUBULAR AUXILIARY CONTACT MEMBERS AND OTHER END IN COMMUNICATION WITH THE ATMOSPHERE BY WAY OF SAID EXHAUST VALVE WHEN OPENED. 